Steering mechanism for tractors



Oct. 22, 1929. E J, wlLsoN 1,732,626

STEERING MECHANISM FOR TRACTORS Eil'ed Sept'. 5f 1925` 6 Sheets-Sheet l W- w. M

W5 ATTORNEYS Oct. 22, 1929. E, J, WILSON i 1,732,626

STEERING MECHANISM FOR TRACTORS y Filed Se t. 5, 1925 6 h e s-Sheeb 2 l JU W Oct. 22, 1929.

E. J. WILSON STEERING MECHANISM FOR TRACTORS Filed Sept. 5, 1925 6 Sheets-Sheet 5 INVENTOR Cet. 22, 1929.

E. J. WILSON STEERING MECHANISM FOR TRACTORS Filed sept. 5, 1925 6 Sheets-Sheet 4 SM mais;

KQ ATTORNEYS N w ,V w

E. ll. WILSN STEERING MEGHANISM FOR TRACTORS wmf, :im wm.

6 sheets-sheet 5' Filed sept. 5, 1925 111W w E, 1, WILSUM f STEERING MECHANISM FOR Timmons l Filed sept. 5, 1925 5 sheets-sneek' e l l i xNvENToR w 41;, ATTORNEYs.

Patented Oct. 22, 1929 j-IEMERY J. WILSON, OF CLEVELAD, OHIO, ASSIGNOR TO THE THEW SIIOVEL COMPANY,

OF LORAIN, OHIO, A. CORPORATION OF OHIO STEERING' MECHANISM FOR TRAGTORS 'l Application ledl September 5, 1925. Serial No.

My invention relates to steering mechanism tor tractors, and more particularly to steering mechanisms for tractors'of the endless tread or track laying type wherein the steeru ing is edected by controlling the operating of a pair of clutches in the lateral driving connections for the tractor.

llt is an object olf my invention to e'ect the steering ot a tractor in a highly elticient manlu ner by more emcient utilizing the power ot the rotating turntable carried on the vehicle to operate the driving clutches, than has heretotore been done,-so tar as l am aware.

Another object-ot my invention is to prol vide tor the resilient application ot power tor selectively operating either or both of the driving clutches whereby the vehicle may be steered and/or propelled.

Another object ot my invention is to pro- 20 vide tor the absorption oi anyand all undue stresses that might otherwise be imparted Ato parts ot the steering linkage through rotation ot the turntable.

Another object ol mv invention is to provide tor controlling ot the clutches whereby they may both be held in a neutral non-driving osition whenever, for instance, the tractor is eing towed.

.luuother object oit my invention is to per- 3U ,mit one of the clutches to be set under the contlll lill

trol of the rotating turntable to either driving, neutral or locked position whereby there' will be communicated a driving e'ort from the engine vor other motor carried by the turntable to its associated track driving roller, to discontinue such driving eli'ort, or to lock the said driving roller and the track operated thereby in a fixed position, respectively.

Another object of my invention is to effect the positioning oi either of the two companion clutches in any one of the aforesaid operative positions, or in neutral pos1t1on, and the other clutch in any of said operative positions or neutral position.-

Atnother object ci my invention is to rou vide a mechanism of the class describedw ich shall be relatively inexpensive to manufac ture, but which, at the same time, will effect the functions sought to be performed by the mechanism in a highly efficient manner, and

arm.

which willvnot be readily deranged or broken 1n use.

Another object of my invention is to provide as a unitary piece of apparatus a springset, by virtue of which the clutches may be eciently controlled and restored, and which will provide an elastic shock absorbing link in the line of communicated motion from the turntable tothe clutches.

@ther objects of my invention and the invention itself will be more clearly understood y reference to the accompanaying drawings illustrating an embodiment oi" my invention and in which drawings* Fig. l shows a vertical transverse cross-section of an embodiment ot my invention, comp prising a track-laying tractor truck supportlng a rotatable turntable, the line of section being in the plane of the aligned driving axles of the vehicle..

Fig. 2 is a top plan view ot age comprising a bifurcated steering arm employed in the embodiment ot Fig. l, also with certain related parts largely indicated by dotted lines.

Fig. 8 is an elevational view of certain parts together with vertical sectional view of other parts taken on the line 8-3 of 2.

Fig. l shows mostly in elevation a portion of the apparatus of Fig. 3 ina dili'erent operative position. V

Fig. 5 is a vertical section taken on the line .5*5 of Fig. 2, viewed from the end of the truck which carries the bifurcated steering controlling link- Fig. 6 is an elevational vievT of a portion .of the controlling mechanism, viewed from the steering arm end of the truck.

Figs. 7, 8 and 9 show partly in top plan and I partly in horizontal sectional View, certain of the apparatus illustrated in Figs. 2 and 5.

eferring now to all of the figures of drawing, and more particularly to Fig. l and t0 the various parts shown therein, which are indicated thereon by suitable reference characters, like characters in each ligure desig-L nating like parts, at l, I show a turntable supporting a superstructure 2 comprising a housel which, in the embodiment of my invention illustrated herein, may contain the driving engine or motor, and driving connections co-operating therewith, whereby the bevel gear 3, keyed onto the center pin shaft 4, may be driven to communicate motion to y the driving axles 5 and 6 to propel the vehicle.

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. pinion 11 is carried y porting endless tracks locking the non-driving roller and its track 18 carries at i The turntable 1 is journalled on the center pin 4 and is rotatable thereon, being supported by rollers such as 7, 8 and others, not in the usual way for a vehicle of this kind, on a track 9. 'The track 9 has vgear teeth 10 formed at its periphery adapted to cooperate with the teeth on the pinion 11; the on a shaft 12 journalled in an arm 13 of the turntable frame and noncentrally thereof, whereby rotative motion may be imparted to the turntable by the driving connections from a driving shaft 14 to the shaft 12 throughbevel gears 15 and 16.

The center pin 4, carries at its lower end, a bevel pinion 17 meshing with a beveled gear 18 journalle'd in the frame 19. The bevel gear its two ends jaw clutch elements 20 and 21. The jaw element 21 vis disposed, preferably as shown, within the recess provided in the face of the bevel gear 18 and is arranged'concentrically with the bevel gear teeth. The driving axles 5 and 6 have track ldriving rollers 22 and 23 securedto their re-l spective ends for communicating the driving effort of the driving shafts to the vehicle supillustrated at 24 and 25, and upon which the vehicle is propelled.

Sliding jaw clutch elements 26 and 27 are splined onto the driving shafts '5* and 6 respectively, and are adapted to key their respective shafts to the jaw clutch elements 20 and 21, respectively, whenever it is desired to communicate driving motion to the driving roller served by the one or the other of the respective driving shafts. Clo-operating fixed jaw clutch elements 28 and 29 are provided for the slidin jawy clutch elements .26 and 2 7 and adapte to be engaged thereby when the sliding jaw clutches are advanced into operative engagement therewith, to lock the drivin shaft whereon such sliding clutch is spline 1 The effect of the provision of the elements above -generally described is to provide a track-laying truck mechanism carrying a rotatable turntable upon which may be carried, the engine or motor mechanism, and comprising driving connections adapted to rotate the turntable relative. to the chassis frame of the vehicle, and adapted to propel the vehicle by operating one or both of the driving rollers associated with the endless tracks thereof, and to permit turning of the vehicle by operation of only one of the driving rollers, and the turning movement may be accentuated .by

from movement.

Generally speaking, in the embodiment illustrated, the operation of the clutches is accomplished by communicating the power of the rotating turntable through suitable linkage to the sliding clutches, such linkage being hereinafter more specifically described, reference being had more particularly to figures of drawing other than Fig. 1.

Referring now more particularly to Figs. 2 to 4 inclusive, and Figs. 6, it will be seen that the superstru'ctive turntable frame 1 carries a rotatable shaft 30, the said shaft having an operating lever arm 31 secured at one end thereof; the shaft is journalled in extensions 32 of the frame 1, and at its other end the shaft 30 hereinafter called the steering pin lever shaft,` carries a steering latch piu 33 upon which there is journalled a steering latch roller 34, the pin 33 being rigidly and relatively non-rotatively secured to the rod 30.

To the end of the lever 30 a chain 35 is affixed, the chain 35 preferably normally extending upwardly and adapted to be secured to latch 36 as illustrated in Fig. 3. The effect of lifting-the chain 35 is to rotate, the shaft 30 clockwise as seen in Figs. 3 and 4, to lift the steering latch roller 34 to its horizontal position as shown in Fig.4, or when the chain Iis released the roller 34 will drop to the position shown in Fig. 3.

Suitable linkage comprising a steering arm 36 and complementary steering arm roller 37,'link connections 38 and 39, forked side bar members 40 and 41, a steering compression spring 42, a safety compression spring 43, and jaw clutch shifting levers 44 and 45 are provided for the purpose of communicating movement of the turntable 1 to the clutches whenever the steering latch roller 34 is first placed in the complementary position shown in Fig. 3 wherein it is embraced by the bifurcated end 46, ofthe steering arm `36.

The steering arm 36 is journalled on a pin 47 secured to the chassis frame 19 and is likewise bifurcated at 48 to admit the -1 steering arm roller 37 between the forks thereof as illustrated in Figs. 2, 3 and 9. Link connection means comprising levers 38 and 39 carry a in 50 upon .which the steering arm rol er 3 is journalled the levers 38 and 39 are adapted to swing about a pin 51 rigidly secured to an extension 52 rof the truck chassis frame 19. The pin 51 acts as a fulcrum for the jaw clutch shifting lever 44. The `levers 45 and 44 are adapted to be rotated'on their respective ins 51 and 54 under the control of the meclianism comprising the steering compression spring and the safety compression spring as will be now described. I

After the steering latch roller 34 is first placed between the forks of the steering arm 36, motion effective to move slidable jaw clutch elementsV 26and 27 may be lselectively communicated from the link connection lethe pressure of the connecting rod 63 tively.

mitted through the center `1s screw-threaded at shifting are'moved vto the left, as seen in Fig. 8. The forked side bar elements 40 and 41 will be moved thereby to the right, this being effected by virtue of the pins 55 and 56 which hinge the link levers 38 and 39 to the side bar members 40 and 41, respectively; side bar members 40 and 41 being moved to the left as seen in Fig. 5 will move thecrosshead element 57 to the left compressing' the safety lcompression spring 43 whereby pressure from the end 59 of the spring will be eXert ed against the peripheral dang-e of the cupshaped safety spring center element 60, rllhis will resiliently apply pressure from the end wall 61 of the elementv 60 against the shoulder 62 of the connecting rod 63.

e connecting rod 63 has 'a reduced end 64 and is screw-threaded at its other end as lshown at 65 to a connecting1 rod 66, whichA carries at its remote threaded end, an adjusting nut 69. The end 67 of the connecting rod 63 will communicate pressure eXerted toward the left as illustrated against the clutch shifting lever at its `iaw rend 68 and will rotate this jaw clutch shifting lever 45 in a clockwise dlrection, as viewed in Fig-8, about its fulcrum pin 51. .llt the same time, will be clutc-h shifting lever jaw adjusting nut 70, which 71 into a hollow flanged center piece 72loosely fitted onto the connecting rod 66, and the pressure transmitted by its danged head 74 through compression spring 42 by the flanged center piece72 will be effective to move the jaw 75 of the otherjaw clutch shifting lever 44 to rotate it in clockwise direction as viewed in Fig. 8.

The relative position of the parts after being operated as described, and after the jaw clutches have been thereby caused to be shifted, is illustrated in Fig. 8, `wherein the jaw clutch shifting levers 45 and 44`are both shown as being rotated to their ultimate extreme position in the direction of clockwise rotation, and the clutch engaging arms thereof 76 and 77, respectively, which are fitted into grooves 78`,.and 79,`- respectively, of the sliding j aw clutches 27 and 26, respectransmitted by the 68 to the threaded upon motion being transpin driving shaft bevel gear 18, the rotated to rotate the 1n this position,

4, Fig. 1, to rotate the drive shaft 5 will be recti'onof travel toward the left.

.direction that .ment 59 being the steering usting nut 69 on the rod 66.

`press the spring 42 to' resiliently a roller 22, but the driving shaft 6 will be i held stationary since the jaw clutch element 27 splined onto the shaft 6, by virtue of the interlocking of jaws 8l and 82 of uthe sliding clutch element 27 and of the fixed clutch .element 29 respectively, is locked against roable and the vehicle will swerve from the dii This operation is initiated by a counter-clockwise swingingof the turntable under steering conditions, which connection link levers 38 and 39 described.

In other words, if, as is commonly the case, a forwardly extending boom is carried by the turntable of the vehicle, a swinging of the turntable to shift the boom toward the left will steer the vehicle to the left, and as will be now seen, the contrary is likewise true, .that the vehicle will steer to the right upon the proper connections being made and the boom being swung to the right.

For turning the vehicle sharply to the right a movement of the turntable in a clockwise direction will be had to effect rotation of the link connection levers 38 and 39 inV` such a as viewed in Fig. 5, the pins 55 will be moved toward the right; exerted by the nearest edges of the slots 86 in the side bar-members 40 and 41, and will betransmitted by the pins 87 to the flanged cup-shaped center element 6l and will exert a pressure against the end 59 of the springy 43, and all pressure will be resiliently trans-I mitted by th crosshead element 59, longitudinal movement of the members 46 and 41 relative to the elepossible by providing slots 157 and 158 in th 88 screw-threaded on the reduced end of the rod 64, transmitting such mot-ion. This will draw the rod 63 toward the right as shown in Fig. 5, and will transmit a movement toward the right to the jaw 75 of the jaw clutch shifting lever 44 by virtue of the adv The motion will e transmitted through the jaw 75 ofthe clutch shifting lever against the left endvvface of the center piece 151, whose flanged head 152 will exert pressure toward the right `Yto 3l through the spring 42 a lever shifting ellbrjt transmitted through the ange-74 of the ccnterpiece 72 and the screw-threaded adjusting nut 70 ailixed to the centerpiece 72 and bearing against the jaw 68 of the other jaw clutch shifting lever 45. y

in suchcase pressure will be a causes the shifting of the d e` compressed spring against the e members 40 and 41 respectively v iso ' 40 1 and 2,- whereupon driving had to both of the tracks,

' to the right,

Therefore, in the latter described case, both jaw clutch shifting levers 44 and 45 will be shifted in such a direction at their jaw ends that as viewed in Fig. 7 they will be rotated counter-clockwise to the position shown in Fig. 7 wherein the sliding jaw clutches are disposed as shown, the jaw clutch 27 being moved into engagement with the jaw clutch element 21 of the double jaw clutch bevel gear 18 torotate the driving shaft 6 by movement transmitted from such bevel gear through the jaw clutch elements 21-27; at the-same time the sliding jaw clutch 26 will have been moved to the position shown in Fig. 7 wherein it will be clutched rigidly in engagement with the fixed jaw clutch 28, thus locking the driving shaft 5 against rotation and preventing rotation of its associated tread 24.

Thus the vehicle upon turntable in a direction a movement of the to swing 'the boom and a forward driving effort being given to thel track driving mechanism, a forward steering of the tractor toward the right will be effected in such case as above described, the propelling track on the right side of the vehicle will be held locked against rotation and the propelling track to the left of the vehicle will exert a driving effort, the result of these two conditions being that the vehicle will be slued towards the right.

Whenever it is desired to propel the vehicle forwardly, but `twithout causing it to swe'rve either to the right or to the left, it is only necessary to restore the turntable to its normal neutral position wherein the boom if one is carried bythe turntable, will bedisosed in neutral forward position whereupon the clutch shifting levers 44 and 45 willl be restored to the position shown in Figs. 1

vno swerving from a straight ahead direction.

It will beunderstood that in the foregoing description it has been assumed that the center pinshaft 4 will be driven by the engine in such a direction as to propel the vehicle forwardly, that is with the boom extended in the direction oftravel, and the'y steering latch in steering position, and it will be obvious that rearward direction of movement may be reversely had to the right or or straightV rearward movement if the direc tion of rotation of the center pin`driving shaft 4 is reversed. This may be -`accomplished in the usual way by reversing the engine carried by the turntable or by the employment of reverse gear or reversing clutch connections such are are very commonly employed in this art.

nl aw clutch neutral latchesA 91 and 92 pivoted on latch pins 93 and 94 which are carried in the frame 81 are provided. for the purpose of retaining the clutch shifting levers 45 and 44 respectively in their neutral connection will beiy and there will be to the left A 98 in the wall of the frame 19 and have outwardly extending handle portions 99, projecting outwardly from the frame to a po-v sition where they may be readily grasped by the operator of the machine. A number of perforations 100 through the rods 95 and 96 and suitably spaced along such rods are provided for adjustment purposes, a pin 101 for each rod being provided whereby a collar 102 may be pinned to each of the rods through a desired one of the said perforations. As shown two of these perforations are herein provided, for each rod the outer perforations being used to position the rods and 96 as illustrated in Figs. 7 and 8 wherein the lat-ches 91 and 92 are withdrawn from holding contact with the jaws 103 and 104 which are integrally secured to the jaw clutch shifting levers 45 and 44, respectively.

It will be noted by referring to Figs. 7 and 8 that in such a case the collars 102 are held against the pierced frame by pins passing through the more remote pair of openings 100, whereas in Fig. 9 this is accomplished by the pins passing through the less remote pair of openings 100.

In order to swing the clutch elements 27 and 26 to the neutral positions illustrated in Fig. 9, wherein the driving axles 6 and 5 are disconnected from driving connection with the double clutch bevel gear 18, the turntable is rotated to the right as illustrated in Fig. 7, and the latch 92 is drawn to latching `position as illustrated in Fig. 9 by pulling on vthe rod 96 and removing the collar 100 pinned to the outermost perforation in the rod 6 and replacing it on the rod 96 in a position where it will be pinned to the less remote opening 100.v The turntable is then rotated to the left until the jaw clutch shifting lever 45 takes the position shown in Fig. 8

and the rod 95 is pulled by its handle 99 to al position wherein its pin 101 may be employed to pass through the collar 102, and the innermost perforation 100 as illustrated in Fig. 9; the turntable is then subsequently returned to neutralposition. In such case the latches 91 and 92 will engage 103 an'd 104 of the levers 45 and 44, respectively, and prevent them from returning to their fully` restored position as illustrated in Fig. 2, which they would otherwise do were it not for the position of the latches 91 and 9,2. The clutches 27 and 26 will thereupon be held in the neutral'positions shown in Fig.9 whereupon the tractor mechanism may be towed -without any driving or locking position being had between the drivin axles 6 and 5 with the driving or locking el provided therefor. l

the spring pressed ]aws utches l olf the illustrated embodiment of from the foregoing description a complete understanding will be had of the operation of the preferred embodiment of my invention illustrated in the drawings.

In the above description I't is believed that of the operation p my invention, reference was had to the various coacting parts, some of which will now be described more in detail. The steering latch 1 c-arrying the roller 34 .has an integrally formed weight portion 108 disposed at right angles to the steering latch roller 34 and is adapted to keep the roller in itslatching po sition', as illustrated in Fig. 3, whenever the chain 34 is sufficiently lowered to permit the i so shaped lever 31, journaled on the latch carrying shaft 30, to turn, due to the weight of the portion 108,' integral with the latch havin the roller 34. A hook 36 is tightly secured on to a rod 109 of the A-frame of the vehicle carried on the forward or boom carried portion of the rotating' frame thereof. Equivalent means for holding the chain 35 may be secured to any fixed portion ofthe vehicle.

The connecting rod, extending substantially axially Within the axially aligned safety compression spring 43 and the steering compression spring 42, is suitably supported at its reduced end 69 by the frame 19, being passed through an aperturedll in the said frame. The compression springs 42 and 43 are preferably of diiferent strengths, the

steering compresslon spring 42 being the` lighter of the twolsprings, the safety com# pression spring 43 being preferably capable of sustaining at least twice the weight or pressure as that of the steering compression spring 42 within its elastic limit. For this reason, theV steering compression spring is made of lighter gauge spring steel than is the other spring, since in practice, it is not called upon tov withstand the pressure imparting shocks to the same degree as is the larger spring.

The reduced portion 64 of the connecting rod 63 which passes through the cross head element 57, is adapted to have a considerable clearance within the longitudinal bore 113 of the cross head, and is capable of swinging laterally within the bore of the Hanged center clement 60, to a limited extent, as illustratedv 1n Figs. 7 and 8.

At 110, Fig. 5, I show a rest pad for the spring mechanism, comprising the springs 42 and 43, to help to support the weight of the intermediate portions of the mechanism, the pad` 110 beingpreferably fixed to the lowermost side bar'element 41 and adapted to slide upon an adjacent portion of the frame 19, not shown.

The steering arm 36 has its bifurcated end as to have converging arcuate edges 112 and 114, and similar inclined inner edges 115 for each fork thereof, all of which pairs m a direction the illustrated preferred shaping of the forks thereof, is to permit the latch roller 34, when pressed, as seen 1n Fig. 3, to engage, if the roller is not dropped within the forks, one of the sides 112 or 114. Asthe turntable continues its rotation the roller 34 will ride along such sides to the tips of the forks, and then after being.A lifted on its pivot rod 30, will drop into the space between the forks, after which the bifurcated steeringlever 36 will carry between its forks the roller 34 and be controlled in its rotative movement about its pivot pin 47 by the roller 34 as moved by the rotation of the carrying turntable. When the turntable is rotated beyond that position which is indicated by dotted lines in Figs. 1 and 2 which position is effective to displace the roller 37 to the position, as illustrated in Figs. 7 and 8, wherein the clutches are shifted to their ultimate extreme positions, right and left, further rotation of the turntable will result in the latching roller 34 riding over the tip of the second fork and passing outside of the space intermediate the forks.

lite-engagement of the steering lever 36 by the controlling roller 34 may be had by again rotating the turntable from either direction to that position wherein the roller 34 `may again enter the space between the forks, in the manner above described. It Awill be seen, by referring to the position of the lever 36, illustrated in Fig. 8 and that illustrated in ing arm 36, may take the ositions of Figs. 7 and 8 wherein the roller 37, herein called the steering arm roller, may have the space 118 between the forks 119 and end,of the steering arm and rides upon the arcuate outer face 121 of the fork 119, Fig. 7 or of the fork 129, Fig. 8. The faces 121 are preferably segments of the same circle and concentric with the axis of the pin 47 upon which the arm 36 is swung, and the retractive pressure exerted upon the fork119, Fig. 7, or in the other position of Fig. 8, upon the curved surface 121 of the fork 120, is exerted which willv produce no operative movement of the steering arm 36, the steering arm relative to such pressure being then in what may be called a dead center or locking position". When the steering arm 36 is moved toward the central position shown in Fig. 9, the retractive pressure tending to restore the link connection members 38 and 39, which support the roller 37 and which pressure is exerted by the compression springs 42 and 43, will cause the roller 37 to be resiliently snapped into the recess 118,

Fig. 7, that in these figures the lever or steerthe turntable is .rotated and the roller de- 7 0 ject to the movements communicated to the arm 36 by movements of the turntable communicated to such arm through the steering arm element 36 through roller 34. It will be seen that these compression springs tend to restore the operating levers comprisingl the link connection elements 38 and 39 and the jaw clutch shifting levers 44 and 45 to normal osition.

Although I have n t shown in detail all of the driving connections between the treads 24 and 25 andthe engine or motor which would be provided to drive such treads and the gear connections within the treads, whereby motion will be communicated between the driving motors 22 and 23 to such treads, these may be of any well-known form or type suitable to perform the functions intended and related herein, and they may be ofthe type disclosed in my `former application, Serial No. 756,465, tiled December 17, 1924, and the co-pending applications referred to therein. The present invention is related to the steerin controlmechanism described and illusclaimed in the accomtrated herein and as panying claims.

It will be observed that by virtue of the arrangement .of the parts described, the turntable may be moved to successive positions from a central position as illustrated in Fig. 9, as follows First-,a positionwhere the driving clutch is just starting driving clutch is released; third, where the holding clutch is released; and, fourth, to `a locking position wherein the clutch operating levers are `by virtue of the relative positions of the steering arm 36 and the roller 37 locked in their operative positions, as illustrated in Fi 7 and 8; and that there is a like series of turntable positions for each direction of turntable rotation from a normal or central turntable position. i

Although I do not wish to be limited to a givenamplitude of turntable swing` to accomplish the different steering functions described, in a machine built according to the drawings and foregoing description, I secured very eicient results by'so arranging the parts,

-as illustrated, that the driving'clutch would start to release upon approximately a rotation of 33/ by the turntable, and that upon a further rotation of about 3, the 'driving clutch releases, and upon a further rotation of 3, the holding clutch releases, after which upon rotating-the turntableto about 63 in ,advancel of the position where the holding tion ofthe levers, as described and shown 1n clutch was released it attains the locking posi- Figs. 7 and 8. Of course," it will be understood that these values wouldbe modified'if, for instance, the steering. lever arm 36 had its fulcrum point. positioned dierently along its length, and that other modifications might be made which would enable the unctions to release;.second, where the .erating the clutches,

122 is provided vto rigidly main'- tain a given adjusted position of the nut 70 relative to the center element 72. At 123, Fig. 3, I show an adjustable screw adapted to be locked by a clamping nut, against which the steering latch 33 may contact to limit its movement to a vertical position under the influence of the weight 108. It will be observed also that I have provided for the jaw clutches and the large bevel gear 18 and driving pinion 17, as well as the other jaw clutch elements 20, 21, 26, 27, 28 and 29, a casing, comprising integral-portions of the lower frame 19 and lower pan element 125, which is oil-proof, for containing lubricant for lubricating the contained moving parts. 1

, I have also provided an oil basin 126 adapted to deflect oil or other lubricant carried by the large gear 18 and dropping on one side of the pan over into the other compartment on the opposite side o the casing, wherein is contained the jaw clutch elements 20,l 26 and 28. I find that this arrangement is verny efficient for the purpose intended and insures always that a suiiicient supply of lubricant will be available and effective to properly lubricate the moving parts mentioned.

While I have described my invention in a specific embodiment, I am aware that numerous and extensive departures may be made from the embodiment herein illustrated and described but without departing from the spirit of my invention and from the scope of the accompanying claims.

I claim as my invention:

1. In a tractor mechanism, the combination with a chassis therefor, of a crawling track at each side of the chassis and supporting the same, a rotatable turntable supported by the chassis carrying a prime mover, driving connections from the prime mover to the crawling tracks, a pair in each driving connection, levers Jfor opa spring connecting the levers and tendingnormally to move them toclose their respective clutches, linkage to communicate motion from the turntable when rotated in one direction to move one of the clutches to open the same, and when rotated in the opposite direction to open the other clutch, and a detent for each clutch adapted to be moved into a position to retain its associated clutch in opened position against the turntable and comprising positlon.

2. In a tractor mechanism, the combination with a chassis therefor, of a crawling track at each side of the chassis and supporting the same, a rotatable turntable supported by the chassis carrying a prime mover, driving connections from the prime mover to the crawling tracks, a pair of clutches one in each driving connection, levers for operating 4the clutches, a spring connecting the levers and tending normally to' move them to close their respective clutches, linkage to communicate motion from the turntable when rotated in one direction to move one ot the clutches to open the same, and when rotated in the opposite direction to open the other clutch, and a detent for each clutch adapted to be moved into a position to retain its associated clutch in open position against the tendency of the spring to return it to closed position, said linkage comprising a part carried by the turntable, adapted to communicate motion to the clutches for only tendency of. the spring to return it to closed a relatively small arc of movement of the turntable.

3. lln a tractor mechanism, the combination with a chassis therefor, of a crawling track at each side of the chassis and supporting the same, a rotatable turntable supported by the chassis carryinga prime mover, driving`-connections from'the prime mover to the crawling tracks, a pair of clutches one 1n each driving connection, levers for operating the clutches, a spring `connecting the levers and tending normally to move them to close their respective clutches, linkage to communicate motion from thev turntable 'when rotated in one direction to move one of the clutches to open the same, and when rotated in the opposite directionto open the other clutch, and a detent for each clutch adapted to be moved into a position to retain its associated clutch in opened position against the tendency of the spring to return it to closed position, said linkage' comprising a part carried by the turntable, communicate motion to the clutches for only a relatively small arc of movement of the yieldable spring means through which pressure is, applied from the turntable to the clutch to be moved.

4. ln a tractor mechanism, the combination with a chassis therefor, of a crawling track at eaclrside of the chassis and supporting the same, a rotatable turntable supported by the chassis carrying a prime mover, driving connections from the prime mover to the crawling tracks, a pair'of clutches one in each driving connection, levers" for operating the clutches, a spring connecting the levers and tending normally to move them to close their respective clutches, linkage to communicate motion from the Aturntable when rotated in one direction to move one of the adapted to b clutches to open the same, and when rotated in the opposite direction to o en the other clutch, and a detent for each c utch adapted to be moved'into a position to retain its associated clutch in opened position against the tendency of the spring to return it to closed position', said linkage comprising a part carried by the turntable, adapted to com municate motion to relatively small arc of movement of the turntable and comprising yieldable spring means through which pressure is applied from th'e turntable to the clutch to be moved, said spring and said spring means comprising parts of a unitary apparatus interposed between y the clutches and the rotatable turntable.

5. In a tractor mechanism, the combination with a chassis therefor, of a crawling track at each side of the chassis and sup..

porting the same, a rotatable turntable supported by the chassis carrying a prime mover, driving. connections from the prime mover to the crawling tracks, a pair of clutches one in each driving connection, levers for operating the clutches, levers and tending normally to move them to close their respective clutches, linkage to communicate motion from the turntable when rotated in one'direction to move one of the clutches to open the same,'and when rotated in the opposite direction to open the other clutch, and a detent for each clutch adapted to be moved into a position to retain its associated clutch in opened position against the tendency of the spring to return it to closed position, said linkage comprising a part carried by the turntable, adapted to communicate motion to the clutches for only a relatively small arc of movement of the turntable, and an interposed lever for communicating motion from the turntable car ried part to the clutches, said part and said interposed lever having complementary contacting portions comprising a bifurcated projection of the one portion adapted to emrace a projecting arm of the other portion, that complementary portion carried by the turntable carried part being adapted to be carried by the continued movement of the turntable out of operative engagement with the other complementary portion.

6.*In a tractor mechanism, the combination with a chassis therefor, of a crawling track at each side of the chassis and supporting the same, a rotatable tugnta ported by the chassis carry-ing a'prime mover, driving connections from the prime mover to the crawling tracks, a pair of clutches one in each driving connection, levers for operating the clutches, a spring connecting the levers and tending normally to move them to close their respective clutches, linkage to communicate motion from th when `rotated one direction` t Vmove one a spring connecting the- 'turntable the clutches for only a ble supy turntable,

its associated of the clutches to open -it to closed position, said linkage comprising la part carried by the turntable,

adapted to communicate motion to the clutches for only a relatively small arc of movement of the and an interposed lever for communicating motion vfrom the turntable carriedl part of the clutches, said part and said interposed lever having complementary contacting portions comprisin-g a bifurcated projection ofthe one portion adapted to embrace a projecting arm of the other portion,

that complementary portion carried by the turntable carried part adapted to be carried by the continued movement of the turntable out of possible contact with the other complementary portion, and locking means for the clutches adapted to retain a clutch in opened position, upon movements. of the turntable beyond a rotative position thereof wherein operative engagement is rendered impossible between said contacting portions.

7. In a tractor mechanism, the combination with a chassis therefor, of a crawling track at each side of the chassis and supporting the same, a rotatableturntable. supported'by the chassis carrying a prime mover,

' driving connections from the prime mover to 'the crawling tracks, a pair of clutches one in each driving connection, levers for operating the clutches, a spring connecting the levers and tending normally to move them to close their respective clutches, linkage to communicate motion from the turntable when rotated in one direction to move one of the clutches to open the same, and when rotated in the opposite direction to open thev other clutch, and a detent for each lclutch adapted to be moved into a position 'to retain its associated clutch in opened position against the tendencyof the spring to return it to closed position, said linkage comprising a part carried by the turntable,

vadapted to communicateA motion to the i turntable carried part of the clutches,

clutches for only a relatively small arc of movement of the turntable, and an interposed lever for communicating motion from the said part and said interposed lever having complementary contacting portions comprising a bifurcated projection of the one portion i adapted to embrace a projecting arm of the other portion, thatcomplementary portion carried by the turntable carried part adapted to be carried by the continued movement of the turntable out of possible contact with the other complementary portion, ing' means for the clutches adapted to retain a clutch in opened position, upon movements of the turntable beyond val rotative position and lockthereof wherein operative engagement is rendered impossible between said contacting portions, said locking means to be disabled upon re-contact of the said contacting portions when the turntable is returned.

8. In a tractor mechanism, the combination with a chassis therefor, of a crawling track at each side of the. chassis and supporting the same, a rotatable turntable supported by the chassis carrying a prime mover driving connections from the prime mover to the crawling tracks, a pair of clutches one in each driving connection, levers for operating the clutches, a spring connecting the levers and tending normally to move them to close lheir respective clutches, linkage to communicate motion from the turntable when rotated in one direction to move one of the clutches to open the same, and when rotated in the opposite direction to open the other clutch, and a detent for each clutch adapted to be moved into a position to retain its associated clutch in opened position against the tendency of the spring to return it to closed position, said linkage comprising a part carried by the turntable, adapted to communicate motion to the clutches for only a relatively small arc of movement of the turntable, and an interposed lever for communicating motion from the turntable car- `ried part of theclutches, said part and said interposed lever having complementary contacting portions comprising a bifurcated projection of the one portion adapted to embrace a projecting arm of the other portion, that complementary portion carried by the turntable carried part adapted to be carried by the continued movement of the turntable out of possible contact with the other complementary portion, and locking means for the clutches adapted to retain a clutch in opened position, upon movements of the turntable beyond a rotative position thereof wherein operative engagement is rendered impossible betweensaid contacting portions, said locking means ada ted to be disabled upon a re-engagement o the said contacting portions when the turntable is returned, said locking means comprising an actuatin lever interposed between the said interposed lever and the clutch levers, said actuating lever being movable to either of two extreme positions and to an intermediate position, and having a free end, said interposed lever engaging said end of the actuating lever when moved to operate the clutch levers, actuating lever engaging an end face of one of the forks of said interposed lever when said lever is moved to an extreme position and locked thereby.

9. AIn a crawling tractor mechanism comprising a pair of crawling tracks disposed at the sides of the mechanism, a driving connection adapted to communicate drivsaid being adapted i said clutch, a spring interposed between the closing pressure thereon,

o carried by clutch levers and adapted to exert clutch closing pressure thereon, a rotatable turntable they tractor mechanism, means to communicate pressure derived from motion of the rotatable turntable against an end of said spring to cause one of said-clutches to open its respective clutch and to exert clutch, closing pressure against the. other lever, detent means for each clutch to maintain it in open position after being moved thereto. o

l0. In a crawling tractor mechanism comprising a pair of crawling tracks disposed at the sides of the mechanism, a driving connection adapted to communicate driving motion to each track, a clutch 'in said ldriving connection, a clutch lever for each said clutch, aspring interposed between `the clutch levers and adapted to exert clutch closing pressure `thereon, a rotatable turntable carried by the tractor mechanism, means to communicate pressure derived from motion of the rotatable lturntable against an end of said spring to cause one of. said clutches to open to exert clutch closing pressure again t the other lever, said pressure communicating means includingr a spring, detent means for each clutch to maintain it after being moved thereto.

ll. In a crawlingv tractor mechanism comprisino a pair of crawling tracks disposed at the sides of the mechanism, a driving connection 'ada ted to communicate driving mot-ion to eaclli track, a clutch in said driving connection, afclutch lever for each said clutch, a spring interffosedbetween the clutch levers and,v adapted to exert clutch a rotatable turntable carried by the tractor mechanism, means to communicate "pressure derived from motion of the rotatable turntable against an end of said spring to cause one of said levers to open its respective clutch and to exert clutch closing pressure against the `other lever, .said pressure communicating means comprising a spring. l

In testimony whereof I hereunto aliix my signature this 1st day of September, 1925.

(itt

EMERY` J. WILSON.l

its respective clutch and in open position 

